<template>
    <div>
        <router-link tag="div" 
        to="/" 
        class="header-abs"
        v-show="showAbs">
           <div class="iconfont header-abs-back">&#xe667;</div>
        </router-link>
        <div class="header-fixed" 
        v-show="!showAbs"
        :style="opacityStyle">
            <router-link to="/">
               <div class="iconfont header-fixed-back">&#xe667;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>
<script>
export default {
    name:'DetailHeader',
    data() {
        return {
            showAbs:true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handleScroll () {
            const top = document.documentElement.scrollTop
            if (top > 60) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = { opacity }
                this.showAbs = false
            } else {
                this.showAbs = true
            }
        }
    },
    activated () {
        window.addEventListener('scroll',this.handleScroll)
    },
    deactivated () {
        window.removeEventListener('scroll',this.handleScroll)
    }
}
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl'
.header-abs
  position :absolute
  left :.2rem
  top :.2rem
  width :.8rem
  height :.8rem
  line-height :.8rem
  text-align :center
  border-radius :.4rem
  background :rgba(0,0,0,.8)
  .header-abs-back
    color :#fff
    font-size :.4rem
.header-fixed
  z-index :2
  position :fixed
  top :0
  left :0
  right :0
  height :$headerHeight
  line-height :$headerHeight
  text-align :center
  color :#fff
  font-size .32rem
  background :$bgColor
  .header-fixed-back
    position :absolute
    top :0
    left :0
    width :.64rem
    text-align :center
    font-size :.4rem
    color :#fff
</style>